Process for classifying iron shot



NOV. 10, 1953 T T 2,658,616

PROCESS FOR CLASSIFYING IRON SHOTS Filed April 14, 1950 l7 INVENTOR: A {a MILO J, STUTAN 40 H Patented Nov. 10, 1953 PROCESS FOR CLASSIFYING IRON SHOT Milo J. Stutzman, Kansas City, Mo., assignor to Olin Industries, Inc., East Alton, 111., a corporation of Delaware Application April 14, 1950, Serial No. 155,905

4 Claims. 1

This invention relates generally to the manufacture of shot, and particularly to the recovery of shot of sphericity usable as the projectile in shot shells from a heterogeneous mixture thereof with non-spherica1 shot.

In years past, the shot used as the projectile charge in shot shells has been made of lead, or lead alloys. Although from time to time it has been proposed to make such shot of iron or steel,

until recently no economic process was available whereby steel shot of usable sphericity might be made on a mass scale. Even with the processes recently proposed for the manufacture of iron shot, the yield of poor sphericity is inordinately high, as compared with the yield thereof in lead shot manufacturing operations. With lead, the particles whose sphericity is too poor to permit their use in ammunition are, for the most part, in the form of tear drops, and no great difficulty has been encountered in separating them from the nearly spherical pellets which are usable in ammunition. Iron shot, on the other hand, assume a variety of odd shapes, which cannot be separated from the sufficiently perfect spheres with the facility which the tear drops could be separated from nearly perfect spheres of lead.

In the separation of the well-shaped from the poorly-shaped lead shot, it was customary to provide a lass plate in the form of an isosceles triangle, tilted about the base as an axis, so that the vertex opposite the base is elevated; then to deposit the shot upon the glass plate near the elevated vertex, so that the shot of usable sphericity would roll rectilinearly toward the base, while the non-spherical pellets veered from rectilinear travel toward the converging sides of the triangular plate, and were thus separated. For a number of reasons such a device cannot be depended upon to adequately separate iron shot into spherical and non-spherical fractions, and consequently it is the object of the present invention, generally stated, to provide a process for separating spherical from non-spherical iron shot. The word spherical is used herein in the practical, rather than the geometric, sense, as connoting shot of sufliciently good sphericity to permit their use as the shot charge in shot shells.

A further object of the invention is to provide a process for grading shot into different fractions according to the degree of sphericity.

Other objects will become apparent to those skilled in the art when the following description is read in connection with the accompanying drawings, in which:

Figure 1 is a perspective view of one form of 2 apparatus suitable for grading shot, in accordance with the present invention;

Figure 2 is an end view of the apparatus shown in Figure 1;

Figure 3 is a perspective view of another form of apparatus suitable for grading shot, in accordance with the present invention;

Figure 4 is an end view of the apparatus shown in Figure 3;

Figure 5 is a plan view of another apparatus suitable for grading, shown in accordance with the present invention;

Figure 6 is an end view of the apparatus shown in Figure 5;

Figure 7 is a sectional view taken along line l? of Figure 6; and

Figures 8 and 9 are, respectively, end views of different modifications of the apparatus shown in Figure 1.

The present invention contemplates that a heterogeneous mixture of spherical and nonspherical shot pellets, which have been roughly separated so as to be of similar size, be graded (as to shape) by depositing the pellets upon a fiat surface (upon which they are individually free to roll), and, while on such flat surface, subjecting the pellets to two different impositive forces, acting athwart each other. Gravity may be, and preferably is, utilized as one of the impositive forces, and to take advantage thereof the flat surface is tilted to such a degree that the spherical pellets will roll readily down the incline under the influence of gravity, thus selectively responding to the action of gravity in preference to the other force, which acts athwart the bias of gravity. On the other hand, the nonspherical pellets are less responsive to the influence of gravity, do not roll so fast or so far, so that, in their delayed travel, they are more subject to the other force.

By shot of similar size, as the expression is used herein, it is intended to embrace all shot of sizes commonly referred to, in the ammunition industry, as shot, which includes all the sizes customarily employed in shot shells.

Where gravity is depended upon as the force to which the spherical pellets are selectively responsive, the other force may take a variety of forms, as for example, a continuous translation of the fiat surface, a jerky oscillation thereof, a magnetic sweep, or a draft of fluid, such as air, it being understood that the second mentioned force must be adjusted in magnitude with reference to the inclination of the surface (i. e., the effect of gravity upon the pellets), so that in any event the spherical pellets are preferentially responsive to the gravitational force. The flat surface across which the pellets roll may be level however, and in lieu of gravity, other forces, such as a draft of fluid, or kinetic energy in the pellets when deposited upon the surface, depended upon to move the spherical ones in a direction athwart the other force.

Referring now to Figures 1 and 2 for an illustrative example of an apparatus capable of carrying out the process of the invention, the device shown is in the general form of a concentrating table, well known in the minerals classification art, with certain modifications adapting it for use in accordance with the present invention. A flat surface I, such as a sheet of glass, or a wooden table covered with a sheet of smooth linoleum or rubber, is provided and arranged to be oscillated jerkily in the direction shown by the arrow. The flat surface I is mounted upon a suitable frame, so as to be free for limited oscillatory movement in the direction indicated by the arrow. To accomplish such oscillation, any of the variety of well-known oscillating mechanisms may be used. That shown in the drawing comp-rises a driven shaft 2, having a crank 3 and a pitman 4. A yoke embraces the pitman, and is connected thereto by a toggle-link 6. The opposite side of the pitman is provided with a toggle-link I, the remote end of which is seated against an abutment 3, mounted on the frame. The yoke 5 is biased in one direction by a spring 9, and is moved against the action of the spring when the pitman 4 moves the togglelinks 6 and 1 toward straight relation, so that the yoke 5 oscillates twice per revolution of shaft 2.

The yoke 55 has a swivel connection II with a rod I2 upon which the table I is mounted, so that the rod- I2, with the associated table, may be tilted about the rod I2 as an axis without interfering with the transmission of oscillatory motion from yoke 5. Any suitable arrangement of parts for adjusting the degree of tilt (about rod I2 as an axis) of the table I may be provided, so that once the proper tilt is determined, the apparatus may be operated continuously at the same degree of tilt.

Mounted adjacent one corner of the table I is a feedbox I3, having a spout I4 arranged to deliver shot onto the surface of table I. At the opposite side of table I from feedbox I3, a series of troughs I5 and I6 are provided, to catch the shot as: it spills over the edge I! of the table I. Two such troughs are shown in the drawings, but it will be understood that a great number thereof may be provided when it is desired to take closer cuts according to sphericity of the shot being processed.

At the end of the table I opposite feedbox I3 a further trough I8 is provided to collect the non-spherical pellets as they spill over the edge I9 of the table I.

With an apparatus of the character just described the spherical pellets, upon. being deposited. on. the surface I, roll immediately under the influence of gravity toward trough I5. The less spherical pellets, being less free rolling, are retarded in their descent, and hence are more influenced by the jerking oscillatory motion which tends to move them toward edge I9. The pellets which fall. just short of usable sphericity are collected in trough I6, while those grossly out-of-round roll very little down the incline, and are discharged over edge I9 into trough I8.

For the separation of spherical from nonspherical pellets which have been roughly separated into fractions corresponding respectively to the popular sizes employed in shot shells, the degree of tilt of table I (so as to make the edge I! lower than the surface immediately beneath spout I4) may be between 1 and 10, the smaller the shot the greater the tilt, but at an inclination of 5:, the apparatus will efficiently grade shot of sizes Nos. 4 to 9, which are the most popular ammunition sizes.

Referring now to Figures 3 and 4, an apparatus is shown wherein, in lieu of the jerky os cillatory motion tending to move the non-spherical pellets endwise, a continuously moving belt 2I is provided, andv driven so as to have its upper surface move in the direction indicated by the arrow. The upper reach of the belt 2I is preferably provided with a supporting surface arranged to maintain the upper surface of the belt 2i flat. In this case, the spherical pellets are collected in trough I5,. the middlings in trough [5, and the poorly-shaped pellets in trough 18, as in the previous. embodiment. With the apparatus shown in Figure 3, the spherical pellets being more free rolling than the non-spherical ones, proceed immediately down the incline toward trough I5, while the less spherical are delayed in their movement down the incline, and are progressed toward trough I8.

In the embodiment shown in Figures 5, 6, and '7, a. flat surface 3I,. tilted as before, so that the feedbox I3 is arranged at a high edge, is provided, but in this case the flat surface 3! is stationary- In order to progress the non-spherical pellets toward edge. 39 while the spherical pellets are rolling. toward edge 31, the surface 3'I is diagonally swept with magnetic flux. This may be accomplished by providing a rotating electromagnet 32 above, but. in spaced relation to, the surface 3I, and extending diagonally thereacross as shown in. Figure 5. The electromagnet 32 may comprise a shaft 33,. mounted in suitable bearings at opposite ends thereof. Four pole pieces 34 and 35 extend radially from shaft 33, and each is provided with a coil which, when energized electrically, magnetizes the respective pole pieces so that. when pole pieces 34 are north, for example, pole pieces 35 are south. It is not necessary to charge the polarity of the several pole pieces during. rotation, but on the other hand, the electromagnet may be energized by alternating current. With the pole pieces 34 and 35 magnetized so as to constitute opposite poles, magnetic flux will travel between them through the adjacent air extending out sufficiently to affect iron or steel shot pellets therebeneath on table 3i, and sweeping the same endwise toward edge 39.

In each form of apparatus shown in Figures 1 to 6 inclusive, gravity is relied upon to move the spherical shot from the feedbox position toward trough I5, but it will be understood that the path followed by such moving shot is, to a limited extent, influenced by the transverse force applied in Figure 1 byjerking, in Figure 3 by continuous movement, and in Figure 5 by the magnetic sweep. Nonetheless, the non-spherical pellets, being less responsive to the pull of gravity than the spherical ones, are delayed in their travel down the incline, and hence are subjected to the endwise pulling influence of the transversely acting secondary force.

In lieu of depending upon gravity to move the spherical pellets diagonally toward trough I5, other types of force may be utilized. In Figure 8,

g the apparatus of Figure 1 is shown with the table 1 level, but the shot is delivered thereto from an elevated feedbox 83 through a tube 84, which is curved so that surface I is substantially tangent with tube 8d at the discharge end 85 thereof. In this embodiment, the spherical shot have sufficient kinetic energy imparted to them, in their fall through tube 94, to roll entirely across table I to trough [5, whereas the non-spherical pellets have insufiicient kinetic energy to roll them so far. The latter dissipate their kinetic energy, and either slow sufficiently, or cease their movement toward edge ll sufiiciently short thereof, that they are moved by the oscillatory jerking action toward trough 18.

Another alternative wherein the table I is operated level is shown in Figure 9. In this instance, the shot are deposited upon table i from feedbox 13, arranged as in Figure 1, but are impelled toward trough [5 by a jet of air delivered from nozzle 99, in a direction substantially parallel with surface I, and addressed toward trough 55. In this case, the free rolling spherical pellets preferentially respond to the draft of air issuing from nozzle 99, and roll readily toward trough 15, whereas the less free rolling nonspherical pellets are moved by the oscillatory jerking action toward trough 18.

It will be readily understood that, in lieu of the oscillatory jerking action for moving the non-spherical pellets toward trough 18 with the apparatus shown in Figures 8 and 9, either the continuously moving surface shown in Figure 3 or the magnetic sweep shown in Figure 5 may be employed, the latter only when the pellets are of magnetic material, such as iron or steel.

From the foregoing description, those skilled in the art should readily understand that the invention accomplishes its objects, and provides a process whereby a mixture of spherical and nonspherical shot may be readily separated into fractions graded according to the degree of sphericity. While several embodiments of apparatus suitable for carrying out the process have been herein described, it is to be understood that such apparatus is suggested merely by way of illustration, and not by way of limitation on the invention. Any suitable impositive forces applied to the shot pellets in directions athwart each other, and so coordinated one with the other that the spherical pellets are preferentially responsive to the one, may be adopted without departing from the spirit of the invention, and it is contemplated that those skilled in the art will resort to other types of impositive force to accomplish the separation according to sphericity. It is therefore to be distinctly understood that the invention is not limited to the details of the foregoing disclosure, but that many modifications and variations thereof are contemplated by and within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In the art of classifying iron shot of similar size into spherical fractions and less spherical fractions, the process comprising rolling all the shot freely across a smooth surface which inclines in at least one directionat from 1 to 10 with the horizontal, subjecting the shot while rolling upon the surface to a force acting in a direction transverse to the inclination of the surface, collecting shot at different positions along the lower edge or said surface, said spherical fraction being collected at a position reached by shot which roll substantially perpendicularly to said force, and said less spherical fraction being collected at a position reached by shot which roll more obliquely with respect to the direction. of said force.

2. The process of claim 1 wherein the transverse force is applied by jerkily oscillating the surface.

3. The process of claim 1 wherein the transverse force is applied by moving the surface continuously in the transverse direction.

4. The process of claim 1 wherein the shot is magnetic and the transverse force is applied by a magnetic sweep.

MILO J. STUTZMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 402,904 Conkling May 7, 1889 451,370 Conkling Apr. 28, 189-1 703,320 Tatham June 24, 1902 823,234 Wait June 12, 1906 1,044,067 McKesson et a1. Nov. 12, 1912 1,141,852 Sutton et al June 1, 1915 1,283,284 Payne Oct. 29, 1918 1,292,820 Lindsley Jan. 28, 1919 1,409,307 Morava Mar. 14, 1922 1,625,257 Ingolfsrud Apr. 19, 1927 1,729,589 Mordey Sept. 24, 1929 2,281,174 Steele Apr. 28, 1942 

